文摘
Supercritical water oxidation (SCWO) progress for a spherical activated carbon particle waspursued using a flow-type reaction cell equipped with sapphire windows, where the change inthe size and shape of the particle inside the cell was observed in real time by means of ashadowgraph. While maintaining its shape, the particle radius decreased almost linearly withtime at a rate on the order of micrometers per second. Phenomenologically, the reaction occurredat the surface of the sphere. The decreasing rate of the radius was nearly first order with respectto the O2 concentration and was almost independent of the temperature and pressure in thecell. On the other hand, the rate increased with the flow rate of the supercritical water. Thesetrends suggested that the reaction was almost limited by the mass transfer of O2 from the bulkto the surface of the particle. The observed rate roughly agreed with the rate of O2 mass transferwhich was estimated using empirical relations.